The Democratic Governors Association said its call to match the Murdoch contribution raised $1.7 million. Ginning up a fight with Fox News, which is owned by the News Corporation, “helped fire up the base,” said Nathan Daschle, the association’s executive director.

That is what cable news does now: fire up the base.

Even more than they did than in 2008, Fox News Channel and its left-leaning counterpart MSNBC are playing outsize roles in the midterm elections this year. Attacking the news media is time-honored in politics, but the recent fund-raising efforts show how some candidates and groups have been directing their attack ads this year not at other candidates, but at cable television.

Marco Rubio, the Republican Senate candidate in Florida, said in a Web ad over the summer that his economic plan must be right because the MSNBC host “Rachel Maddow thinks it’s wrong.” Christine O’Donnell, the Republican Senate candidate in Delaware, criticized “the liberal media led by Rachel Maddow and Keith Olbermann” in an e-mail pitch last month — conveniently next to the “Donate Now” button.

And also last month, Ted Strickland, the governor in Ohio, who is in a tough fight against the Republican John Kasich, a former Fox News host, incorporated Mr. Murdoch’s $1 million donation in a fund-raising appeal.

Conversely, Fox is drawing attention as a fund-raising platform for Republicans. Last week Mr. Kasich was given time to promote his campaign Web site on “Hannity,” a prime time program on Fox News. Mr. Kasich told viewers, “If you have extra nickels or dimes, please send it our way.”

As for tougher programs like “Meet the Press,” which is a production of NBC and is replayed on MSNBC, she asked, “Well, in that audience will they let me say I need $25 dollars from a million people — go to SharronAngle.com, send money?”

Alex Conant, a Republican strategist who is advising Gov. Tim Pawlenty of Minnesota, said some politicians, like Representative Michele Bachmann, a Minnesota Republican, had “clearly benefited fund-raising-wise by having a higher profile.”

But he also observed that “some of the campaigns that have raised the most money haven’t gone on cable at all.”

The influence of cable will almost certainly extend into the next presidential election, since a number of potential candidates for the Republican nomination are on the payroll of Fox News, including Mike Huckabee, who has a show on the weekends, and Sarah Palin.

The politicization of cable news has been a long time coming. Still, it was striking to see Glenn Beck of Fox News hold a religious-themed rally in Washington in August, and to see Ed Schultz, who is the host of programs on MSNBC and on radio, kick off a progressive rally there this month.

Jon Stewart and Stephen Colbert of Comedy Central are staging a rally in Washington next Saturday, but Mr. Stewart says it will not be political.

The evolution of cable hosts from observers to outright opponents has sometimes been a source of frustration. Ms. Maddow said on her show this month, “For those of us who work here at MSNBC, one of the most surreal things about this particular election year, has been conservative politicians’ efforts to make us part of the elections.”

Ms. Maddow bemoaned the fact that politicians like Mr. Rubio and Senator Scott Brown, Republican of Massachusetts, invoke her in ads and e-mail appeals, but turn down her interview requests.

Photo

Rachel Maddow, the MSNBC host.Credit
Virginia Sherwood/NBC

Because Fox is the most popular cable news channel by far — lately it has been averaging about 1.5 million viewers at any given time on the weekdays, more than CNN and MSNBC combined — it draws enormous scrutiny from liberals for what they perceive to be a right-wing bent in both the news and opinion programming. Mr. Olbermann now calls Fox News “FoxPAC,” the insinuation being that the network is a political arm of the G.O.P., in part because of Mr. Murdoch’s donation.

This week the billionaire financier George Soros said he was donating $1 million to Media Matters, a liberal media monitoring group, to step up the group’s fight against Fox.

Phil Griffin, the president of MSNBC, and others strenuously object to the idea that Fox and MSNBC are opposite sides of the same coin. “Show me an example of us fund-raising,” he said in a recent interview.

Those examples exist at Fox. The channel was the subject of an election complaint in Ohio because Mr. Kasich was able to ask for money and display his Web site address during an interview in August on “The O’Reilly Factor,” Fox’s biggest prime time talk show. Mr. Kasich used to host a weekend show on Fox, and Mr. Murdoch has called him a friend.

Mr. Daschle, whose group filed the complaint, called it “free advertising,” and recited Mr. Kasich’s claim in a campaign speech that he raised over $21,000 in the 12 hours after the interview. The association withdrew its original complaint in order to amend it; Mr. Daschle said it would file a new complaint soon.

A spokeswoman for Fox News said the channel declined to comment for this article.

All this political activity has spurred at least a little bit of hand-wringing at the channels. NBC News, which operates MSNBC, recently reiterated its rule that employees may not engage in political activity, but said it had carved out an exception for some MSNBC hosts.

Sometimes the most outspoken of the Fox hosts go out and raise money directly. Mr. Hannity has headlined several fund-raisers for Republicans this year. And just last week, Mr. Beck donated $10,000 to the U. S. Chamber of Commerce to defend it against criticism from President Obama — and challenged his radio listeners to donate as well. He wanted to make it the chamber’s biggest fund-raising day ever.

“In the first hour, we beat that goal,” he bragged on Fox News later that day.

A version of this article appears in print on October 24, 2010, on page A24 of the New York edition with the headline: Candidates Running Against, and With, Cable News. Order Reprints|Today's Paper|Subscribe